Mixer



June 27, 19 50 BENSON 2,512,603

MIXER Filed Jan. 14, 1948 INVENTOR- Patented June 27, [950- UNITED STATES ATENT OFFICE MIXER Bradley L. Benson, Glendale, Calif. Application January 14, 1948, Serial No. 2,221

- 3 Claims.

and relates to a device for mixing and extruding,

aggregate materials.

The objects of the invention include: The provision of a revolving, drum-type container provided with means whereby, when said drum is revolved in one direction the content of said drum will undergo continuous mixture, and, when said drum is revolved in reverse direction, the content thereof will be continuously evacuated therefrom;

' Selective means for, optionally, mixing or evacuating, either periodically or continuously; A mixer of such structure that the component parts thereof can be joined, for operation as a unit, and wherein none of said parts requires application of power to move it with respect to the other parts;

A mixer that can be readily cleaned by introducing water, or a dry abrasive material, such as sand, after mixed material has been evacuated.

Other objects and advantages will become apparent as this description proceeds.

In the accompanying drawings (one sheet) Figure '1 is a side view of a composite drum member, a portion of which is'broken away for the purposes of illustration;

' Figure 2 is an end view of Fig. 1;

Figure 3 is an opposite end view of Fig. 1;

Figure 4 is a vertical, longitudinal, cross-sectional view of Fig. 1;

Figure 5 is a vertical cross-sectional view of Figs. 1 and 4, taken on the dotted lines V-- V of said figures, illustrating the functionsof certain parts when my mixer is revolved in a direction efiecting mixture'of its content;

Figure 6 is a view similar to Fig. 5, illustrating the movement of mixed material while my mixer is being revolved in a direction reverse to that indicated in Fig. 5 (:r), to effect evacuation of its mixed content;

Figures 7 to 12, inclusive, are vertical, central, cross-sectional views of the component parts of my mixer, as they would appear if. the end closures, shown in Figs. 1 and 1, were removed and the assembled parts withdrawn, Figure '7 being a cap, Figure 8 a spider-like impeller, Figure 9 a disc, or circular plate, Figure 10 'a'cylindrical tube, Figure 11 a convolute bafiie-member, andFigure 12 a closure or cap;

Figure 13 is an 'end View of Fig. 11;

Figure 14 is a longitudinal, sectional view ofa sectional or multiple-cell mixer, made by duplication of the members shown in Figs. '7 to 1'2'. inclusive;

Figure 15 is a. side view of my mixer in one form it can assume as a stationary mixer, showing the device illustrated in Figs. 1 and '4- sup ported on trunnions, and driven by an internal combustion engine;

Figure 16 is an end view of Fig. 15;

Figure 17 is a, side view of a typical installation of my invention, wherein are shown selective means for mixture in transit; and

Figure 18 is a top plan view of Fig. 17.

Referring to the drawings: Fig. 1,-the numeral l designates a cylindrical tube, preferably formed from a rectangular piece of sheet metal of a thickness calculated to withstand the weight of the-commodities, or materials, to be mixed.

Said sheet is welded at the confronting edgesconventional pipe fittings for the samepurpose, except for intake and delivery ports therein, and

a threaded sleeve member l5, Fig. 14,. like a standard pipe coupling- Within the composite drum, composed of cylinder I, the caps 2 and 3, are three co-acting members 6, 'l, and, 8 which are, respectively, a spider-like impeller, acircular disc, and a convolute bafile.

These three members are shown, assembled, in operative relation, in vertical cross-section in Fig.

4 and said members are shown in Figs. 7 to 12',

inclusive, as having been successively withdrawn from drum l for individual illustration.

The impeller 6 is here represented as having six legs, but more, or fewer, may be employed whenever physical characteristics of aggregate to be mixed may make a change expedient.

The divergent legs of said impeller are first cut from flat, sheet metal stock, then bent at 9, Fig.

6, and the major portion of each leg is rolled to a curvature approximating that of the periphery of drum I.

The convergent, straight, portions of said legs are welded, at their ends, to a tube I! and said legs are spaced, radially, by triangular, flat metal plates I2, in oblique relation shown in Figs. 4 and 8.

When so assembled, the edges of plates I2 are welded to adjacent legs, forming a unitary impeller provided with a conic body, with the apex of the cone at the center of a discharge port I3, Figs. 2 and 7, while the legs radiate, tangentially, from the periphery of said discharge port, when the parts are assembled as in Figs. 1 and 4.

The disc I, Fig. 9, is centrally bored, at IE, to admit therethrough the tube II, which is threaded at I! to engage a, nut I8 which removably secures disc I to the impeller 6, in concentric relation thereto.

In Figs. 11 and 13, I show a convolute bailie' member 8, the ends 8a, of which are bent inwardly toward the central axis around which the member 3 is wound, for the purpose of fending against cap 2 and/or disc I, when the parts assembled as in Fig. 4, are revolved, on the longitudinal axis of the mixer.

It is to be understood that the only power applied to operate my mixer is just what is required to rotate the drum, and that the impeller 6 and the disc 'I, secured thereto, are engaged, between cap 3 and the end of cylinder I, by the threaded connection of said parts.

All parts rotate as a unit, except the convolute bafile 8 which, when the drum I is empty (or nearly so), rolls independently within said drum, making more revolutions per minute than said drum does, because of its smaller diameter.

The convolute member 8 has several distinct functions, some of which come into play only when aggregate reaches certain levels within drum 1.

The mixture of aggregate A, within drum I, and the subsequent evacuation thereof from said drum, are accomplished solely by progressive gravitation of the material itself, in response to revolution of said drum by extraneous power.-

Typical examples of power application for this purpose are shown in Figs. 16 and 17.

In Fig. 16, drum I is shown as being revolvably supported on trunnions I 9, journalled in bearings 2| bolted, at 22, to a deck or foundation as for a stationary mixing plant.

Drum I is provided with a belt, or ring-gear 23, which meshes with a worm gear 24, secured to a shaft 26, driven by an internal combustion engine 21, provided with a reverse gear mechanism, controlled by a gear-shift lever 28, adapted to drive shaft 26, selectively, in either direction.

In electrically-driven installations a reversible split-phase motor would replace the engine 21, and a motor-control switch, in circuit with said motor, would supplant gear-shift mechanism 28.

In Figs. 17 and 18, I show one example of the use of my mixer as a portable unit with a different application of power applied thereto, making it serviceable, upon occasion or demand, as a transit mixer.

In this instance, trunnions I9 are journalled in bearings integral with a. frame member 29 of a vehicle chassis supported on wheels '3I, at the rear end, and, at the front, by an extensible foot 32 swivelled on the end of a shaft 33 rotatable by a hand wheel 34.

Shaft 33 is threaded through frame 29, at 36,

4 to make foot 32 retractible, when the vehicle is to be towed, as by a coupling, or hitch, 31.

Drum I is revolved by an endless sprocket chain 38 which engages sprockets on the belt 23 and also sprockets on a sprocket-wheel 39, movable, selectively, into engagement with an axle-driven member, in a well-known manner (for mixing in transit) or with a motor 21 secured to a deck surmounting frame 29, for use as a portable mixer.

Operation The operation of my invention will be better understood by referring to an abandoned application for patent, Method and Means for Mixing Concrete, filed by me on July 26, 1947, Serial Number 763,834, to which attention is respectfully called.

Material to be mixed is introduced to my mixer through an intake port Ill, in cap 3, by shovel, chute, conveyor belt, or any feeding device, depending upon the size and type of equipment and whether the operation is to be continuous or intermittent.

Assuming that the installation takes the form illustrated in Fig. 16, adaptable to batch, periodic, or continuous mixing, aggregate material is fed into the mixing chamber, cylinder I, through intake port Ill.

Batch mixing Aggregate, thus admitted, comes to rest on the bottom of cylinder I and, if said cylinder be in motion counter-clockwise, as in Fig. 5, wherein direction of rotation is indicated by the arrow M, mixing will be continuous with no evacuation from said chamber, the revolving drum I carrying the aggregate mass A around to its angle of repose, indicated in heavy dotted lines R.

When said angle is reached, the crest of the advancing mass breaks and cascades across the fiat chord R, and this action continues as long as the mixer is revolved.

During this cycle of operation the convolute baffle 8 functions, first, to prevent the aggregate A from slipping backward, as a mass, and idling inertly on the bottom of cylinder I, and, secondly, to act as a bafile, dispersing the cascading material A, laterally, near the beginning and near the end of its travel across the chord R. as the cascading material encounters one side of the spiral 8 and then the other side.

During the rotative movement of drum I from one end of chord R to the other, the entire mass A undergoes complete mixture and this mixture occurs three times during each revolution of drum I, making the mixture rapid, certain, and con-- tinuous.

During the mixing cycle of operation no discharge occurs, due to the fact that the legs of the impeller 6 pick up very little material when ro-v Pour "To evacuate cylinder I, and pour the mixture A through delivery port I3, gear-shift lever 28 is manipulated to reverse position, andthe cylinder I revolved in clock-wise direction indicated, in

Fig. 6, by the arrow P.

When thus revolved the blades, or legs, of spider I pick up, successively, considerable quantitles of material A, as indicated in dotted lines mt Q, Fig. 6, said quantities gravitating progres- The width of the blades of impeller 8, theloverall diameter f the disc "I, and the speed of rotation or drum I.

iThese variables can be selected to suit the physical characteristics of material mixed.

It will be noted that the disc 1, Figs-4, 5,.and .6, ;is'considerab1y smaller in diameter thanlthe insidediamete'r of cylinder I, thus providing an annular recess 40, Fig. 5, which isdivided into cells by the legs of impeller I.

Said. cells are filled by the cascading material Aseeking a level in drum I. r

iii"

The purpose of the diametrically disposed members 8a is to cause the convolute 8 to bear against disc I, at one end, or cap 3, at the opposite end, and thus prevent any engagement of said convolute with the legs of impeller 6, since said impeller and said convolute revolve at differ-- ent rates of speed.

Cleaning To clean my mixer, after a run of plastic or cementitious material, a quantity of water, or suitable solvent, or some dry abrasive material, such as sand, can be introduced and run through the mixer, in the same manner as heretofore described, and all parts thereof will be washed or scoured, since rotation of drum I will distribute the cleansing medium throughout the interior of the mixer.

At the end of a run, after supply of material has been discontinued, rotation of drum l lowers the level of material A and when said level nears the bottom of cylinder l, the convolute bafiie 8 exercises another function, that of a conveyor.

Due to the pitch of said convolute 8, the last remnants of aggregate are propelled toward impeller 6 which picks up and delivers said material through discharge port l3.

M uZtipZe-stage mixing It is sometimes desirable to efiect mixture of certain aggregates by stages, or to mix two or more constituents before addition of others.

This can be effected as shown in Fig. 14, wherein a duplication of parts, heretofore described, produces a multiple-cell mixer driven as before, consisting of mixing chambers A and 3.

Two of the cylinders l are joined in end-to-end relation by a sleeve coupling l5.

Interposed between the confronting ends of said cylinders l are a disc la, provided with a concentric opening l3a, and a duplicate impeller 6.

In this installation, dry material can be mixed in chamber A diverted into chamber B by impeller 5, and then wet by fluid directed through a nozzle, not shown, inserted through tube II, and the wet aggregate can be then mixed and poured as heretofore described.

The progressive movement of material through the multiple-stage mixer is indicated by a series v said material is very light in weight and, when a relatively small percentage of batch, or mass of material A, that is undergoing mixture, is in movement at any one time, and that this movement is continuous, I have found that I can successfully mix a maximum percentage of pumice in the mix ratio, required bygovernment specifications, to insure the requisite characteristics of lightness and durability in the finished product, and keep the mixture homogeneous until it is finally placed. I

Summarizing the advantageous features of my invention it will be noted: That the mixer is composed ofsix interchangeable parts, and that said part'sare of such structure that they can be manufactured from stock material, without dies, jigs, or patterns, making for economy in production; 1

That the assembly has no doors but is separable for ready access to the interior; that it is extensible, when required, for capacity or multiple-stage mixing; that the mixer is virtually selfscouring and that the operation of mixing and pouring are accomplished, at will, for periodic, intermittent, or continuous service, and can be actuated selectively, in response to push-button controls.

A minimum of power is required for the operation since all the movement of material, to mix and to extrude, results from gravitation of said material, responsive to revolution of the mixer, as a unit.

My invention is useful in various industries, wherever uniformity of and agitation is required, such as in the preparation of food products to formula, mixture of pigments, in paint manufacture, and the treatment of ores.

While the invention is here shown in the form considered to be the best, it is not limited to such form because it can be embodied in other forms, and it is to be understood that, in this specification and the appended claims, it is desired to cover the invention in whatsoever form it may be embodied.

I claim:

1. In a mixer, of the revolving drum type, wherein aggregate material is tumbled within a mixing chamber and eventually evacuated through a discharge port, a dispensing means, for eifecting such evacuation, comprising a spider member provided with a plurality of vane extending radially from the axis of rotation of said mixer to the perimeter of its discharge port, thence tangentially to the inner wall of the mixing chamber of said mixer, said vanes being so disposed as to form a plurality of convergent chambers closed, on one side, by the innerwall of said mixing chamber and, on the opposite side, by a disc secured to said spider, in concentric relation thereto, said disc being of a radial diameter less than that of the inside of said mixing chamber thereby forming intake openings leading into said convergent chambers, means, automatically responsive to revolution of said mixer, in one direction, for conducting material entering said openings to and through the discharge port of said mixer, and, for returning said material to said mixing chamber when said mixer is revolved in reverse direction.

2. A mixer comprising a cylindrical drum, closresulting in an unequal performance in mixture 7 ures for the ends of said' drum provided. with intake" and discharge ports, extrusion me'ans,-*for evacuating said drum, comprising a spider having a centrally disposed body portion, substantially in the form of a cone-with its apex near thecenter-of said discharge port, and having a plurality 'of legs extending, tangentially; from the base of said cone to the inner peripheral wall of said drum, and a diaphragm, interposed between the mixing chamber of said drum and said spider, smaller in diameter than said mixing chamber and providing passages for conducting material within said chamber to, and through, the discharge port of said-drum, and means for revolving all of said members, as a unit, in forward or reverse direction, optionally:

3. The combination, with the elements recited in claim 2 of a 'bafiie member, comprising 'a single length of stock material wound helically in the form of an open-coil spring, adapted to roll freely on the floor of said drum when said drum is re 1 .volved.

BRADLEY L. BENSON.

8 REFERENCES CITED I The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 792,778 Koneman June 20, 1905 841,841 Abbe Jan. 22, 1907 1,048,738 Sanbom Dec. 31, 1912 1,060,419 Benjamin Apr. 29, 1913 1,187,959 Ash June 20, 1916 1,702,931 Cook Feb. 19, 1929 2,167,243 Lichtenberg et a1. July 25, 1939 2,360,344 Hilkemeier Oct. 17, 1944 2,422,989 Skogg June 24, 1947 FOREIGN PATENTS Number Country Date 275,103 Italy Dec. 19, 1927 

